Quantum-controlled measurement device for quantum-state discrimination

-symmetric quantum state discrimination

1Department of Physics, King’s College London, Strand, LondonWC2R 1LS, UK 2Mathematical Sciences, Brunel University, Uxbridge UB8 3PH, UK 3Physics Department, University of Chicago, Chicago, IL 60637, USA 4Helmholtz-Center Dresden-Rossendorf, PO Box 51 01 19, 01314 Dresden, Germany 5Department of Physics, Renmin University of China, Beijing 100872, People’s Republic of China 6Tomsk State Univer...

Quantum state discrimination

It is a fundamental consequence of the superposition principle for quantum states that there must exist non-orthogonal states, that is states that, although different, have a non-zero overlap. This finite overlap means that there is no way of determining with certainty in which of two such states a given physical system has been prepared. We review the various strategies that have been devised ...

Information-Disturbance Tradeoff in Quantum State Discrimination

When discriminating between two pure quantum states, there exists a quantitative tradeoff between the information retrieved by the measurement and the disturbance caused on the unknown state. We derive the optimal tradeoff and provide the corresponding quantummeasurement. Such an optimal measurement smoothly interpolates between the two limiting cases of maximal information extraction and no me...

Experimental measurement-device-independent quantum key distribution.

Quantum key distribution is proven to offer unconditional security in communication between two remote users with ideal source and detection. Unfortunately, ideal devices never exist in practice and device imperfections have become the targets of various attacks. By developing up-conversion single-photon detectors with high efficiency and low noise, we faithfully demonstrate the measurement-dev...

High-rate measurement-device-independent quantum cryptography